From US 2006/0183590 A1 an infinitely variable transmission device with power branching is known. The power splitting takes place by virtue of a planetary transmission device arranged on the transmission input side, a first power path of the transmission device being supplied with torque by a sun gear of the planetary transmission device and a second power path by a ring gear of the planetary transmission device. The sun gear of the planetary transmission device is actively connected with a first shaft of the variator by spur gearteeth. A second shaft of the variator is connected to a gearshift transmission device in this case made as a countershaft transmission. In their region the torques transmitted along the two power paths of the transmission device are summed and passed out of the transmission device via a transmission output.
Disadvantageously, this transmission device occupies a lot of structural space since the gearshift transmission device is arranged between the planetary transmission device and the variator. In addition the active connection between the sun gear of the planetary transmission device and the first variator shaft has to be formed by an undesirably long connecting shaft, which can only be used by virtue of a bearing arrangement in the transmission device which is of elaborate design, giving rise to high manufacturing costs.